#include <stdio.h>
int main ()
{
	int x;
   	printf("Please input the grade :");
	scanf("%d",&x);
	if(x>=90&&x<=100)
	printf("A");
	else
	{
	    if(x>=80&&x<=89)
		printf("B");
		else
		{
			if(x>=70&&x<=79)
			printf("C");
			else
			{
				if(x>=60&&x<=69)
				printf("D");
				else
				{
					if(x>=0&&x<60)
					printf("E");
					else
					{
						printf("Error!\n");
					}
				}
			}
		}	
	}
	
	

}
